Computer aided three dimensional (3-D) reconstructions of Bodo, sp, a unicellular free-living kinetoplastid, were made from ultrathin (100 nm) and semithin (200 nm) sections observed by transmission electron microscopy. Profiles of organelles and membrane systems were digitized into a computer and three-dimensional images were generated using the SYNU software package and the facilities at the San Diego NCMIR. It was observed that the internal disposition of structures like the contractile vacuole, the Golgi complex, the mitochondrion, and the nucleus is very well determined relative to each other and to the cytostome and flagellar pocket, although they are not apparently connected. The contractile vacuole fills a considerable volume of the cell. Volume alterations ocurting during systole/dyastole cycles of the contractile vacuole are compensated for by cytoskeletal adaptations. In detergent extracted cells we observed that a set of curved microtubules separated the flagellar pocket and that the cytopharynx was surrounded by supporting microtubules. Morphological evidence indicates that the flagellar pocket may not be the site of vacuolar content elimination. A manuscript detailing this work has been submitted to the European Journal of Cell Biology.